Supco ld290 Limit Thermostat 290F 3 Wire Open on Rise

Product Description

The SUPCO ld290 is a three-wire heater limit thermostat that opens on temperature rise, designed to protect heating systems from overtemperature conditions. When the sensed temperature reaches 290 degrees F, the thermostat opens the circuit; it resets automatically and closes at 240 degrees F. The 50-degree differential between open and close points provides stable cycling and prevents rapid on-off switching. Termination is made through 1/4-inch quick-disconnect terminals for fast, reliable wiring connections. HVAC technicians and appliance service pros install this type of limit device as a safety control in electric resistance heaters, dryer heating elements, and similar heating assemblies.

This limit thermostat is suited for residential and light commercial heating applications where overtemperature protection is required. Typical installations include electric duct heaters, portable heaters, and appliance heating circuits where a normally closed, open-on-rise safety limit is specified. The three-wire configuration supports applications that require both a normally closed contact path and a monitoring or reset circuit. Service technicians should verify that the replacement thermodisc matches the original open and close temperature ratings before installation.

Key Features

• Opens at 290 degrees F to interrupt the circuit on overtemperature
• Closes at 240 degrees F for automatic reset with a 50-degree F differential
• Three-wire design supports normally closed contact and additional circuit functions
• 1/4-inch quick-disconnect terminals for fast field wiring
• Thermodisc-style construction suited for surface-mount or clamped installation in heating assemblies

Compatibility

Designed as an OEM-style replacement limit thermostat for electric heaters, heating appliances, and similar equipment requiring an open-on-rise safety cutout rated at 290 degrees F.

Installation Notes

Installation should be performed by a qualified HVAC technician or appliance service professional. Disconnect all power to the unit before removing or installing the limit thermostat. Ensure the thermodisc makes firm, full contact with the mounting surface so the temperature-sensing element reads accurately. Verify that terminal connections are fully seated on the quick-disconnect tabs and that no wiring is routed near sharp edges or heat sources.

Technical Specifications

• Open Temperature: 290 degrees F
• Close Temperature: 240 degrees F
• Temperature Differential: 50 degrees F
• Action: Open on rise
• Number of Wires: 3
• Terminal Type: 1/4-inch quick-disconnect

Standard Information

• Brand: SUPCO
• Manufacturer Part Number: ld290